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Class 7–8 General Knowledge: Science practice questions

Practise science for Classes 7 and 8. Try the 10-question quiz below and see each answer explained straight away, then read all 14 questions with answers underneath. Free, no sign-up.

All science questions with answers

1. Which blood cells help to fight infection?

   1. A. Plasma
   2. B. White blood cells ✓
   3. C. Platelets
   4. D. Red blood cells

   Answer: White blood cells. White blood cells defend the body against germs.

2. Water turns into vapour at what temperature at sea level?

   1. A. 100 °C ✓
   2. B. 212 °C
   3. C. 50 °C
   4. D. 101 °C

   Answer: 100 °C. Water boils at 100 °C at sea level.

3. Which metal is liquid at room temperature?

   1. A. Mercury ✓
   2. B. Copper
   3. C. Iron
   4. D. Aluminium

   Answer: Mercury. Mercury is the only common metal that is liquid at room temperature.

4. Which of these is a good conductor of electricity?

   1. A. Rubber
   2. B. Plastic
   3. C. Wood
   4. D. Copper ✓

   Answer: Copper. Metals like copper let electricity pass easily.

5. Which part of a plant absorbs water from the soil?

   1. A. Flowers
   2. B. Fruits
   3. C. Leaves
   4. D. Roots ✓

   Answer: Roots. Roots take in water and minerals.

6. Which force pulls objects towards the Earth?

   1. A. Gravity ✓
   2. B. Friction
   3. C. Pressure
   4. D. Magnetism

   Answer: Gravity. Gravity pulls everything towards the centre of the Earth.

7. What do we call animals that eat both plants and animals?

   1. A. Herbivores
   2. B. Carnivores
   3. C. Omnivores ✓
   4. D. Decomposers

   Answer: Omnivores. Omnivores eat both plants and animals.

8. Which gas forms the largest part of Earth's air?

   1. A. Oxygen
   2. B. Hydrogen
   3. C. Carbon dioxide
   4. D. Nitrogen ✓

   Answer: Nitrogen. Air is about 78% nitrogen.

9. Sound cannot travel through which of these?

   1. A. Steel
   2. B. Air
   3. C. Water
   4. D. A vacuum ✓

   Answer: A vacuum. Sound needs a material to travel through; a vacuum has none.

10. What is the process by which green plants make their food?

    1. A. Photosynthesis ✓
    2. B. Respiration
    3. C. Digestion
    4. D. Evaporation

    Answer: Photosynthesis. Plants use sunlight, water and carbon dioxide to make food.

11. Which vitamin do we get mainly from sunlight?

    1. A. Vitamin C
    2. B. Vitamin D ✓
    3. C. Vitamin A
    4. D. Vitamin K

    Answer: Vitamin D. Our skin makes vitamin D in sunlight.

12. What is the hardest natural substance?

    1. A. Iron
    2. B. Marble
    3. C. Gold
    4. D. Diamond ✓

    Answer: Diamond. Diamond is the hardest natural substance.

13. Which instrument measures temperature?

    1. A. Seismograph
    2. B. Barometer
    3. C. Speedometer
    4. D. Thermometer ✓

    Answer: Thermometer. A thermometer measures how hot or cold something is.

14. What is the chemical formula of water?

    1. A. O₂
    2. B. CO₂
    3. C. NaCl
    4. D. H₂O ✓

    Answer: H₂O. Water has two hydrogen atoms and one oxygen atom.

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